I would suggest going with neutrals with beige/taupe/white with anything that is hard to change. Maybe switch the a A new counter top with neutral Formica and a white sink. You would be surprised as to how inexpensive Formica is. But of course then there is a new sink, faucet and a bit of plumbing work.Go to a home improvement store and ask them lots of questions A friend put in bead boards and painted a soft white in bathroom, I think it looks nice. But they are usually glued and nailed so if you ever get tired of it it would mess up the drywall underneath. I've seen wallpaper that looks like beadboard. But I hate wallpaper myself. You could just do a chair rail and paint the above and below in different colors. As for you light, you probably have one of those that is kind of built into the medicine cabinet and have the round bulbs, I am not sure what to suggest, but they are usually separate from the cabinet. Maybe the home improvement stores have a suggestion. I wanted more storage in my bathroom but didn't want to install medicine cabinet, I have a large plain mirror over sink. Plus wanted deeper storage. I found a white stained kitchen cabinet and installed over toilet. It was a discontinued item so got it cheap. It took some getting used to, afraid it would be too big and bulky, but being whiteish made it not seem so. I had been watching for something for at least a year.

Gray is definitely in! If you still want to stay a little traditional and still be modern, I thought these 12" x 24" porcelain (marble look-alike) tile looked pretty cool. Just installed these a few weeks ago. What kind of tub did you go with? Are you going tile with the surround?

That tiny fixture is not going to give you enough light. Is it a full bathroom or just a WC and sink? The problem with a single fixture is that it will become a glare bomb if it provides enough light. What about a semi-flush mount with a drum shade? Paint the ceiling white and then it will bounce some light off the ceiling. This one has an adjustable stem, I believe, so you could play with the height. Or you could try something light this, but I fear you'd get a lot of pattern/ shadow. This one is Ikea. I also have an illuminated mirror from SimpleHuman that just needs to be recharged once in a while. It's extremely helpful for getting light right where you need it. And yes, that paint color is absolutely sucking away any light that you do have, so changing that will help. Good luck! It's a pretty space. I think I have the same faucet!!

New light paint color for the walls pulled from the tile will make a big difference. I would price replacing the counter with a lighter, quieter prefab laminate counter. They aren't terribly expensive and might be within your budget. A six-foot version is around $100 plus install. The color choices are limited. Greys and browns are tricky so be sure to bring a sample home to look at in your light to make sure the undertones work together. https://www.homedepot.com/p/Hampton-Bay-8-ft-Laminate-Countertop-in-Sea-Salt-with-Tempo-Edge-and-Integrated-Backsplash-011312010819529/305470953